2008 Suzuki LT-A400/F, LT-F400/F ATV Service Manual, Page 102Get this manual
1D-26 Engine Mechanical: Valve Seat Width 1) Visually check for valve seat width on each valve faceIf the valve face has worn abnormally, replace the valve2) Coat the valve seat with red lead (Prussian Blue)and set the valve in place3) Rotate the valve with light pressureSpecial tool (A): 0991610911 (Valve lapper set) 2) Fill the intake and exhaust ports with gasoline to check for leaksIf any leaks occur, inspect the valve seat and face for burrs or other things that could prevent the valve from sealing WARNING
Always use extreme caution when handling gasoline
I827H1140070-01 I827H1140068-01
4) Check that the transferred red lead (blue) on the valve face is uniform all around and in center of the valve faceIf the seat width "a" measured exceeds the standard value, or seat width is not uniform reface the seat using the seat cutterRefer to "Valve Seat Repair (Page 1D-28)"Valve seat width "W" (IN& EX Standard: 0.9 1.1 mm (0.035 0.043 in)